My, what a tasty lawn you have
By Sharon Moffat
Chinch bug.
than a little alarming to see your lawn start to decline due to insect damage. Initially, the damage appears slowly, the lawn looks less green and lush, which can be a result of lack of water, but on closer examination may actual- ly be insect damage. Two of the more common lawn pests are chinch bugs and sod webworm. Chinch bugs
A Chinch bugs are in the family of
true bugs, meaning they are members of the order Hemiptera, and they go through an incomplete metamor- phosis. They develop through imma- ture nymph stages until they become adults and will feed on turf at all stages. They have piercing, sucking mouthparts that they use to extract the liquids from the blades of grass. The resulting turf damage from
this mode of feeding is seen on indi- vidual grass blades as small yellow to brown spots where the chinch bugs have inserted their mouthparts. Over- all, affected lawns will start to look dried out and eventually show yellow- ish, circular areas in which the centre portions are worse than the edges as the chinch bugs continue to move outwards to feed on healthier, juicier grass. Chinch bug damage typically
6 • Summer 2015
nice, lush, green, healthy lawn often goes hand-in-hand with gardening. So, it can be more
Sod webworm larvae (inset) and adult (above).
occurs in sunnier areas of the lawn and is often worse when the weather is hot and dry. One method of control is to regularly water your lawn to discour- age chinch bugs. Another point to consider is that
chinch bugs look very similar to another insect called the big-eyed bug. Big-eyed bugs are beneficial insects that are predacious on other insects present in lawns. Samples of the insects found on the lawn showing damage should be taken for identifica- tion to determine whether the chinch bug is actually the main problem. Sampling can be done using a large cylinder (easily made by cutting off both ends of a large can), and pressing it about two inches into the ground over the edge of the damaged area in the lawn. Then, fill the above ground portion with soapy water. Any insects present will come to the surface and can be collected for identification. Sod webworm
Another common lawn pest is sod
webworm; it is the larval stage of these moths that can severely damage grass. Sod webworm larvae feed at the crown area of grass, immediately at the base of the blades above the soil level. This type of insect damage results
in brown, dead patches of
irregular shapes that over time will increase in size. Sod webworms feed
mainly at night and on overcast days. Another indication of sod webworms can be increased bird activity on the lawn and even the presence of holes caused by the feeding of these birds (though if the lawn is also lumpy the birds are more likely to be after night crawlers which can also be a nuisance to homeowners). Sod webworm larvae can usually be found if you dig around at the edges of the damaged areas of grass. In July, in areas where sod webworms are numerous, it is common to find many small, beige to greyish-white moths flying up from lawns when you walk across the grass and disturb them. The adult moths are identifiable by a snout-like body part that protrudes from their heads. Small areas of damage can usually
be controlled with pyrethrin-based insecticides or insecticidal soap solu- tions applied around the edges of the damaged areas. Some of the areas may need to be re-seeded or have new sod laid down to repair the lawn. All lawns will be better able to withstand some chinch bug or sod webworm damage if they are healthy and well-cared for through proper watering and fertiliz- ing. i
Sharon Moffat has a Plant Science degree from the University of Manitoba and has worked for the City of Winnipeg's Insect Control Branch for the last 24 years.
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